Device for data communications between wireless application protocol terminal and wireless application server, and method thereof

ABSTRACT

A device for data communications between a Wireless Application Protocol (WAP) terminal and a WAP server, and a data communication method thereof. The data communications device includes: a plurality of WAP terminals each having a protocol stack in which a Circuit Switch Data service (CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, for generating WAP data which is service request data; a plurality of WAP servers each having a protocol stack in which a Transmission Control Protocol (TCP) layer and an Internet Protocol (IP) layer are laid under a WTP layer and a WDP layer, for providing the WAP terminals with WAP server data according to the WAP data; and an interworking function (IWF) unit having a CSD protocol layer connected to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP layer which are connected to the TCP and IP layers of each WAP server, for mapping the WAP terminals to the corresponding WAP servers, wherein each WAP terminal communicates with the IWF unit though a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSD protocol layer, and the IWF unit communicates through the Internet with each WAP server. Because there is no redundancy of IP/PPP protocol layers in the WAP terminal, overhead is considerably reduced. Also, the IWF unit is directly connected through the Internet to the WAP server, not through the PSTN and the ISP, so that connection time and costs can be reduced.

This is a divisional of application Ser. No. 09/249,091 filed Feb. 12,1999 now U.S. Pat. No. 6,490,291; of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to data communications, and moreparticularly, to a device for data communications between a WirelessApplication Protocol (WAP) terminal and a WAP server, and a methodthereof.

2. Description of the Related Art

In general, a WAP server is connected between an Internet server whichprovides various information and a WAP terminal capable of receiving theinformation provided from the Internet server, to convert different dataformats and different protocols between the Internet server and the WAPterminal. Also, the WAP server can provide the WAP terminal with its owninformation.

FIG. 1 is a block diagram of a conventional data communications devicebetween a WAP terminal and a WAP server.

The data communications device of FIG. 1 comprises a WAP terminal 10, aninterworking function (IWF) unit 12, a public switched telephone network(PSTN) 13, an Internet service provider (ISP) 14 and a WAP server 16.

The IWF unit 12 performs routing functions between the WAP terminal 10and the ISP 14. The ISP 14 is one of companies providing generalcommunication service such as HITEL or UNITEL. The WAP server 16provides the WAP terminal 10 with its own information and muchinformation from an Internet server (not shown).

FIG. 2 shows a protocol stack of each block of the data communicationsdevice shown in FIG. 1.

A protocol stack of the WAP terminal 10 consists of a plurality ofprotocol layers including a Circuit Switch Data services protocol(CSD(IS-707)), a Peer-to-Peer Protocol (PPP), an Internet Protocol (IP),a Wireless Transaction Protocol (WTP) and User Data Program Protocol(UDP), a Wireless Session Protocol (WSP) and a Wireless ApplicationEnvironment protocol (WAE). Also, the CSD(IS-707) includes an IS-95protocol, a Radio Link Protocol (RLP), a PPP, an IP and a TCP. Theprotocol layers are well known to those skilled in the art, soexplanation thereof will be omitted.

FIG. 4 is a diagram illustrating data flow in the data communicationsdevice shown in FIG. 1.

The operation of the data communications device of FIG. 1 will bedescribed with reference to FIG. 4.

It is assumed that the WAP terminal 10 intends to receive Internet orelectronic mail (E-mail) services. Here, the WAP terminal 10 is ready toreceive a common call or data (Internet or E-mail) in a normal state.When a user of the WAP terminal 10 connects the WAP terminal 10 throughthe IWF unit 12 and the PSTN 13 to the ISP 14 using a telephone numberfor connection with the Internet, the ISP 14 connected to the WAPterminal 10 allows the user to receive the Internet or E-mail services.Also, when the user wants to stop receiving the Internet services, theISP 14 disconnects the call from the WAP terminal 10, returning to theready state.

In detail, the WAP terminal 10 sends an Origination Message requestingconnection of its call to the IWF unit 12. The IWF unit 12 receives theOrigination Message from the WAP terminal 10, and then sends anOrigination Ack message acknowledging reception to the WAP terminal 10.The IWF unit 12 sends a Connect Request message for connection of amodem to the ISP 14. The ISP 14 receives the Connect Request message andsends a Connect <rate> message indicating the connection of the modemthrough the PSTN 13 and the IWF unit 12 to the WAP terminal 10. Underconditions that the WAP terminal 10 and the IWF unit 12 are connected toeach other, the WAP terminal 10 sends WAP data (Internet or E-mailservices request data) which the user wants to receive through the IWF12 and the ISP 14, to the WAP server 16. After the WAP server 16receives the WAP data, the WAP server 16 sends WAP server data which isretained in the WAP server itself, or data taken from an Internet server(not shown) through the ISP 14, the PSTN 13 and the IWP 12 to the WAPterminal 10.

The data communications device of FIG. 1, having the protocol stack asshown in FIG. 2, has the following problems.

First, because the CSD(IS-707) in the protocol stack of the WAP terminal10 includes the IP/PPP as shown in FIG. 3, the protocol stack of the WAPterminal 10 has IP/PPP protocol layers in duplicate. As a result, thereis much overhead during transmission of data, so that transmissionefficiency becomes low. That is, the resources of the terminal are notefficiently used. Also, when a user intends to connect to the WAP server16 or the Internet, connection with the ISP 14 is achieved through thePSTN 14. Thus, the connection rate becomes slow, and using the PSTN andthe ISP 14 may be subject to charges by the telephone company or theISP. Also, the transmission of data is inefficient because it requiresmultiple steps as shown in FIG. 4.

SUMMARY OF THE INVENTION

To solve the above problems, it is a first object of the presentinvention to provide a device for data communications between a WirelessApplication Protocol (WAP) protocol and a WAP server, adopting aprotocol stack in which a single Internet Protocol/Peer-to-Peer Protocol(IP/PPP) layer included in a Circuit Switch Data services (ISD) protocolof the WAP terminal is used and an interworking function (IWF) unit alsoacts as an Internet service provider (ISP).

It is a second object of the present invention to provide acommunication method of the data communications device for the firstobject.

It is a third object of the present invention to provide a device fordata communications between a WAP terminal and WAP server, whichperforms data communications while performing switching between the WAPterminal and a non-WAP terminal.

It is a fourth object of the present invention to provide acommunication method of the data communications device for the thirdobject.

Accordingly, to achieve the above first object, there is provided adevice for data communications between a Wireless Application Protocol(WAP) terminal and a WAP server, comprising: a plurality of WAPterminals each having a protocol stack in which a Circuit Switch Dataservice (CSD) protocol layer is laid under a Wireless TransactionProtocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, forgenerating WAP data which is service request data; a plurality of WAPservers each having a protocol stack in which a Transmission ControlProtocol (TCP) layer and an Internet Protocol (IP) layer are laid undera WTP layer and a WDP layer, for providing the WAP terminals with WAPserver data according to the WAP data; and an interworking function(IWF) unit having a CSD protocol layer connected to the CSD protocollayers of each WAP terminal, and a TCP layer and an IP layer which areconnected to the TCP and IP layers of each WAP server, for mapping theWAP terminals to the corresponding WAP servers, wherein each WAPterminal communicates with the IWF unit through a single InternetProtocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSDprotocol layer, and the IWF unit communicates through the Internet witheach WAP server.

To achieve the second object, there is provided a communication methodof a data communications device including a plurality of WAP terminalshaving a protocol stack in which a Circuit Switch Data service (CSD)protocol layer is laid under a Wireless Transaction Protocol (WTP) layerand a Wireless Datagram Protocol (WDP) layer, a plurality of WAP servershaving a protocol stack in which a Transmission Control Protocol (TCP)layer and an Internet Protocol (IP) layer are laid under a WTP layer anda WDP layer, and an interworking function (IWF) unit having a CSDprotocol layer connected to the CSD protocol layers of each WAPterminal, and a TCP layer and an IP layer which are connected to the TCPand IP layers of each WAP server, for communications between each WAPterminal and each WAP server, the method comprising the steps of: (a)transferring an Origination Message for a call connection from each WAPterminal to the IWF unit, and transferring an Origination ACK from theIWF unit to the corresponding WAP terminal in response to theOrigination Message; (b) receiving WAP data which is service requestdata for the WAP servers from the WAP terminals, to map each WAPterminal to the corresponding WAP server in the IWF unit, andtransferring the received WAP data through the Internet to thecorresponding WAP server; (c) receiving the WAP data to generate WAPserver data according to the received WAP data in each WAP server, andtransferring the WAP server data through the Internet to the IWF unit;(d) receiving the WAP server data transferred in the step (c) to map theWAP servers to the corresponding WAP terminals in the IWF unit, andtransferring the received WAP server data to the corresponding WAPterminals; and (e) communicating in the WAP terminals with the IWF unitthrough a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP) layercontained in each Circuit Switch Data service (CSD) protocol layer ofthe WAP terminals.

To achieve the third object, there is provided a device for datacommunications between a Wireless Application Protocol (WAP) terminaland a WAP server, comprising: a plurality of WAP terminals each having aprotocol stack in which a Circuit Switch Data service (CSD) protocollayer is laid under a Wireless Transaction Protocol (WTP) layer and aWireless Datagram Protocol (WDP) layer, for generating WAP data which isservice request data; a non-WAP terminal for generating a common circuitdata; a plurality of WAP servers each having a protocol stack in whichat least a Transmission Control Protocol (TCP) layer and an InternetProtocol (IP) layer are laid under a WTP layer and a WDP layer, forproviding the WAP terminals with WAP server data according to the WAPdata; an Internet server for providing the non-WAP terminal withInternet server data according to the common circuit data; an Internetservice provider (ISP) having a public switched telephone network (PSTN)circuit layer, for transferring the common circuit data received througha PSTN from the non-WAP terminal, to the Internet server; and aninterworking function (IWF) unit having a CSD protocol layer connectedto the CSD protocol layers of each WAP terminal, and a TCP layer and anIP layer which are connected to the TCP and IP layers of each WAPserver, for performing interfacing between each WAP terminal and eachWAP server, and the non-WAP terminal and the ISP, wherein each WAPterminal communicates with the IWF unit through a single InternetProtocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSDprotocol layer, and the IWF unit communicates through the Internet witheach WAP server.

To achieve the fourth object, there is provided a communication methodof a data communications device including a plurality of WAP terminalseach having a protocol stack in which a Circuit Switch Data service(CSD) protocol layer is laid under a Wireless Transaction Protocol (WTP)layer and a Wireless Datagram Protocol (WDP) layer, a non-WAP terminalfor generating a common circuit data, a plurality of WAP servers eachhaving a protocol stack in which at least a Transmission ControlProtocol (TCP) layer and an Internet Protocol (IP) layer are laid undera WTP layer and a WDP layer, an Internet server for providing thenon-WAP terminal with Internet server data according to the commoncircuit data, an Internet service provider (ISP) having a publicswitched telephone network (PSTN) circuit layer, for transferring thecommon circuit data received through a PSTN from the non-WAP terminal tothe Internet server, an interworking function (IWF) unit having a CSDprotocol layer connected to the CSD protocol layers of each WAPterminal, and a TCP layer and an IP layer which are connected to the TCPand IP layers of each WAP server, for data communications between eachWAP terminal and each WAP server, the method comprising the steps of:(a) determining whether data input to the IWF unit is WAP data or thecommon circuit data; (b) transferring the WAP data through the Internetto the corresponding WAP server if the input data is determined to bethe WAP data in the step (a) and transferring the common circuit datathrough the ISP to the Internet server if the input data is determinedto be the common circuit data in the step (b); (c) determining whetherthe data input to the IWF unit is WAP server data or the Internet serverdata; and (d) transferring the WAP server data through the Internet tothe corresponding WAP terminal if the input data is determined to be theWAP server data in the step (c), and transferring the Internet serverdata through the PSTN to the non-WAP terminal if the input data isdetermined to be the Internet server data in the step (c), wherein eachWAP terminal communicates with the IWF unit through a single InternetProtocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSDprotocol layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects and advantages of the present invention will becomemore apparent by describing in detail a preferred embodiment thereofwith reference to the attached drawings in which:

FIG. 1 is a block diagram of a conventional device for datacommunications between a Wireless Application Protocol (WAP) terminaland a WAP server;

FIG. 2 shows protocol stacks of each block of the conventional datacommunications device;

FIG. 3 is a detailed view of the Circuit Switch Data service protocol(CSD(IS-707) shown in FIG. 2;

FIG. 4 is a diagram illustrating data flow in the data communicationsdevice shown in FIG. 1;

FIG. 5 is a block diagram of a device for data communications between aWAP terminal and a WAP server according to a preferred embodiment of thepresent invention;

FIG. 6 shows protocol stacks of each block of the data communicationsdevice shown in FIG. 5;

FIG. 7 is a diagram illustrating data flow in the data communicationsdevice shown in FIG. 5;

FIG. 8 is a block diagram of a device for data communications between aWAP terminal and a WAP server according to another preferred embodimentof the present invention; and

FIG. 9 is a flowchart illustrating a communication method of the datacommunications device shown in FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 5 showing a device for data communications between aWireless Application Protocol (WAP) terminal and a WAP server accordingto a first embodiment of the present invention, the device comprises aplurality of WAP terminals 50, 52, . . . , and an interworking function(IWF) unit 54, the Internet 55 and a plurality of WAP servers 56, 58 . .. .

Each WAP terminal 50, 52, . . . has a protocol stack in which a CircuitSwitch Data services protocol (CSD) layer is situated below a WirelessSession Protocol (WSP) layer and a Wireless Datagram Protocol (WDP)layer, and generates WAP data which is data requesting data service fromeach WAP server 56, 58, . . . .

FIG. 6 shows a protocol stack of one of the WAP terminals 50, 52, . . .. The protocol stack of FIG. 6 is different from that of theconventional WAP terminal of FIG. 2 in that only a CSD(IS-707) layerexists below the WTP and WOP layers and the IP and PPP layers areomitted. That is, because the CSD(IS-707) layer itself includes the IPand PPP layers as described with reference to FIG. 3, the WAP terminalaccording to the present invention utilizes the IP and PPP layers of theCSD(IS-707), without having IP and PPP layers therein, such that thereis no redundant IP and PPP layers unlike the conventional protocolstack. Each WAP terminal 50, 52, . . . has a unique identificationnumber or source IP address.

Each WAP server 56, 58, . . . has a protocol stack in which a CSD layerexists below a WTP layer and a WDP layer, and a Transmission ControlProtocol (TCP) layer and an IP layer exist, and provides the WAPterminals 50, 52, . . . with WAP server data according to the WAP dataprovided. As shown in FIG. 6, a protocol stack of each WAP server 56,58, . . . has a corresponding structure for each WAP terminal 50, 52, .. . . The WAP server of FIG. 6 is different from the conventional WAPserver in that it comprises the TCP layer which is not shown in theconventional WAP server. Each WAP server 56, 58, . . . has anidentification number or a destination IP address for each source IPaddress of the WAP terminals 50, 52, . . . .

The IWF unit 54 comprises a CSD protocol layer connected to each CSDprotocol layer of the WAP terminals, and TCP and IP layers eachconnected to the TCP and IP layers of each WAP server, to map The WAPterminals 50, 52, . . . to the corresponding WAP servers 56, 58, . . . .Here, the identification number of a specific WAP terminal may be mappedto a destination IP address of the corresponding WAP server, or a sourceIP address of the WAP terminal is mapped to a specific mapping tablevalue. To this end, the IWF unit 54 has a mapping table (not shown) usedfor connecting the identification number of a specific WAP terminal to aWAP server. The IWF unit 54 also includes another mapping table (notshown) which is used for finding the corresponding WAP terminal duringreception of data from a WAP server. The IWF unit 54 and the WAP servers56, 58, . . . are connected through the Internet 55.

FIG. 7 is a diagram illustrating data flow in the data communicationsdevice shown in FIG. 5.

When the WAP terminals 50, 52, . . . send an Origination Message for acall connection thereof to the IWF unit 12, the IWF unit 12 receives theOrigination message and then sends an Origination Ack message as aconfirmation of the reception to the WAP terminals 50, 52, . . . Whenone of the WAP terminals 50, 52, . . . receives the Origination Ackmessage, the WAP terminals 50, 52, . . . being connected to thecorresponding WAP servers 56, 58, . . . , send a WAP data which isservice request data through the Internet 55 to the WAP servers 56, 58,. . . . After receiving the WAP data, the WAP servers 56, 58, . . . sendWAP server data which they retain, or data transferred from an Internetserver (not shown) through the Internet 55 and the IWF unit 54 to theWAP terminals 50, 52, . . . . That is, the WAP terminals 50, 52, . . .are directly connected to the WAP servers without going through anInternet service provider (ISP) using a public switched telephonenetwork (PSTN).

FIG. 8 is a block diagram of a data connection device for communicationsbetween a WAP terminal and a WAP server according to another embodimentof the present invention.

The data connection device of FIG. 8 comprises WAP terminals 80, 82, . .. , a non-WAP terminal 84, an IWF unit 86, a PSTN 87, an ISP 88, theInternet 89, an Internet server 90, and WAP servers 92, 94, . . . .

Each WAP terminal 80, 82, . . . has a protocol stack in which a CSDprotocol is layer resides below WTP and WDP layers, and generates WAPdata for requesting data service to the WAP servers 92, 94, . . . . EachWAP terminal 80, 82, . . . has a unique identification number or sourceIP address.

The non-WAP terminal 84 generates a common circuit data.

Each WAP server 92, 94, . . . has a protocol stack in which TCP and IPlayers 20 are situated below WTP and WDP layers, and provides the WAPterminals 80, 82, . . . with WAP server data according to the WAP data.Each WAP server 92, 94, . . . has an identification number or adestination IP address corresponding to each source IP address of theWAP terminals 80, 82, . . . .

The ISP 88 includes a PSTN circuit layer connected to a PSTN circuitlayer of the IWF unit 86 to be described later, receives the commoncircuit data of the non-WAP terminal 84 through the PSTN 87 andtransfers the received data to the Internet server 90. The ISP 88 is oneof the companies providing general communication services to a commoncarrier.

The Internet server 90 provides the non-WAP terminal 84 with Internetserver data in response to the common circuit data.

The IWF unit 86 includes a CSD protocol layer, TCP and IP layers and aPSTN circuit layer, and acts as interfaces between the WAP terminals 80,82, . . . and WAP servers 92, 94, . . . , and between the non-WAPterminal 84 and the ISP 88. The IWF unit 86 is connected through theInternet 89 to the WAP servers 92, 94, and the IWF unit 86 and the ISP88 are connected to each other through the PSTN 87. The CSD protocollayer is connected to each CSD protocol layer of the WAP terminals 80,82, . . . , and the TCP and IP layers are connected respectively to theTCP and IP layers of each of the WAP servers 92, 94 . . . . Also, thePSTN circuit layer is connected through the PSTN 87 to the PSTN circuitlayer of the ISP 88. In detail, when an input data is the WAP data orthe WAP server data, interfacing is performed such that anidentification number of the WAP terminal is mapped to a destination IPaddress of the WAP server, or a source IP address of the WAP terminal ismapped to a specific mapping table value. Meanwhile, when an input datais the common circuit data or the Internet server data, interfacingbetween the non-WAP terminal 82 and the ISP 86 is performed.

FIG. 9 is a flowchart illustrating a data communication method between aWAP terminal and a WAP server according to another embodiment of thepresent invention.

One of the WAP terminals 80, 82, . . . or the non-WAP terminal 84requests connection to one of the WAP servers 92, 94, . . . or theInternet server 90 (step 902). That is, one WAP terminal or the non-WAPterminal 84 generates a WAP data or common circuit data, respectively,and transfers the data to the IWF unit 86.

The IWF unit 86 determines whether or not the terminal that needs to beconnected in step 902 is a WAP terminal, based on the WAP data or thecommon circuit data (step 904)

If the connection request terminal is a WAP terminal, the WAP terminalis connected through the Internet 89 to the WAP server (step 906).Meanwhile, if the connection request terminal is not a WAP terminal buta non-WAP terminal, the non-WAP terminal is connected through the PSTN87 to the ISP 88, and then to the Internet server 90 (step 908).

The WAP server 92 and the Internet server 90 generate WAP server dataand Internet server data, respectively, and transfer respective datathrough the Internet 89, or the ISP 88 and the PSTN 87 to the IWF unit86.

The IWF unit 86 determines whether or not the input data is WAP serverdata (step 912).

When the input data is from a WAP server, the data is transferred to theWAP terminal. Meanwhile, when the input data is Internet server data,the data is transferred to the non-WAP terminal 84.

The invention may be embodied in a general purpose digital computer thatis running a program from a computer usable medium, including but notlimited to storage media such as magnetic storage media (e.g., ROM's,floppy disks, hard disks, etc.), optically readable media (e.g.,CD-ROMs, DVDs, etc.) and carrier waves (e.g., transmissions over theInternet).

Hence, the present invention may be embodied as a computer usable mediumhaving a computer readable program code unit embodied therein forcommunications between a WAP terminal and a WAP server of a datacommunications device including a plurality of WAP terminals having aprotocol stack in which a CSD protocol layer is laid under a WTP layerand a WDP layer, a plurality of WAP servers having a protocol stack inwhich a TCP layer and an IP layer are laid under a WTP layer and a WDPlayer, and an IWF unit having a CSD protocol layer connected to the CSDprotocol layers of each WAP terminal, and a TCP layer and an IP layerwhich are connected to the TCP and IP layers of each WAP server, whereineach WAP terminal communicates through a single IP/PPP protocol layerincluded in its own CSD protocol layer to the IWF unit, the computerreadable program code means in the computer usable medium comprising:computer readable program code means for causing a computer to effecttransferring an Origination Message for a call connection from each WAPterminal to the IWF unit, and transferring an Origination ACK from theIWF unit to the corresponding WAP terminal in response to theOrigination Message; computer readable program code means for causing acomputer to effect receiving WAP data which is service request data forthe WAP servers from the WAP terminals, to map each WAP terminal to thecorresponding WAP server in the IWF unit, and transferring the receivedWAP data through the Internet to the corresponding WAP server; computerreadable program code means for causing a computer to effect receivingthe WAP data to generate WAP server data according to the received WAPdata in each WAP server, and transferring the WAP server data throughthe Internet to the IWF unit; computer readable program code means forcausing a computer to effect receiving the WAP server data transferredin the step (c) to map the WAP servers to the corresponding WAP terminalin the IWF unit, and transferring the received WAP server data to thecorresponding WAP terminals; and computer readable program code meansfor causing a computer to effect communicating in the WAP terminals withthe IWP unit through a single Internet Protocol/Peer-to-Peer Protocol(IP/PPP) layer contained in each Circuit Switch Data service (CSD)protocol layer of the WAP terminals, for instance.

Also, the present invention may be embodied as a computer usable mediumhaving a computer readable program code unit embodied therein forcommunications transferred between a WAP terminal and a WAP server of adata communications device including a plurality of WAP terminals eachhaving a protocol stack in which a CSD protocol layer is laid under aWireless Transaction Protocol (WTP) layer and a WDP layer, a non-WAPterminal for generating a common circuit data, a plurality of WAPservers each having a protocol stack in which at least a TCP layer andan IP layer are laid under a WTP layer and a WDP layer, an Internetserver for providing the non-WAP terminal with Internet server dataaccording to the common circuit data, an ISP having a PSTN circuitlayer, for transferring the common circuit data received through a PSTNfrom the non-WAP terminal, to the Internet server, an IWF unit having aCSD protocol layer connected to the CSD protocol layers of each WAPterminal, and a TCP layer and an IP layer which are connected to the TCPand IP layers of each WAP server, wherein each WAP terminal communicatesthrough a single IP/PPP protocol layer included in its own CSD protocollayer to the IWF unit, the computer readable program code means in thecomputer usable medium comprising: computer readable program code meansfor causing a computer to effect determining whether data input to theIWF unit is WAP data or the common circuit data; computer readableprogram code means for causing a computer to effect transferring the WAPdata through the Internet to the corresponding WAP server if the inputdata is determined as the WAP data and transferring the common circuitdata through the ISP to the Internet server if the input data isdetermined to be the common circuit data; computer readable program codemeans for causing a computer to effect determining whether the datainput to the IWF unit is WAP server data or the Internet server data;and computer readable program code means for causing a computer toeffect transferring the WAP server data through the Internet to thecorresponding WAP terminal if the input data is determined to be the WAPserver data, and transferring the Internet server data through the PSTNto the non-WAP terminal if the input data is determined to be theInternet server data, for instance.

A functional program, code and code segments, used to implement thepresent invention can be derived by a skilled computer programmer fromthe description of the invention contained herein.

While the present invention has been illustrated and described withreference to specific embodiments, further modifications and alterationswithin the spirit and scope of this invention as defined by the appendedclaims will occur to those skilled in the art.

As described above, the data communications device according to thepresent invention adopts a protocol stack in which only a single IP/PPPprotocol layer resides in the WAP terminals and the IWF unit functionsas an ISP, providing the following effects. First, because there is noredundancy of IP/PPP protocol layers in the WAP terminal, overhead isconsiderably reduced compared to the conventional data transmission.Second, the IWF unit is directly connected through the Internet to theWAP server, not through the PSTN and the ISP, so that connection timeand costs can be reduced. Third, the data flow procedure is alsosimplified compared to the conventional data communications device andmethod thereof.

1. A device for data communications between a Wireless ApplicationProtocol (WAP) terminal and a WAP server, comprising: a plurality of WAPterminals each having a protocol stack in which a Circuit Switch Dataservice (CSD) protocol layer is laid under a Wireless TransactionProtocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer, forgenerating WAP data which is service request data; a non-WAP terminalfor generating a common circuit data; a plurality of WAP servers eachhaving a protocol stack in which at least a Transmission ControlProtocol (TCP) layer and an Internet Protocol (IP) layer are laid undera WTP layer and a WDP layer, for providing the WAP terminals with WAPserver data according to the WAP data; an Internet server for providingthe non-WAP terminal with Internet server data according to the commoncircuit data; an Internet service provider (ISP) having a publicswitched telephone network (PSTN) circuit layer, for transferring thecommon circuit data received through a PSTN from the non-WAP terminal,to the Internet server; and an interworking function (IWF) unit having aCSD protocol layer connected to the CSD protocol layers of each of theWAP terminals, and a TCP layer and an IP layer which are connected tothe TCP and IP layers of each of the WAP servers, for performinginterfacing between each of the WAP terminals and each of the WAPservers, and the non-WAP terminal and the ISP, wherein each of the WAPterminals communicates with the IWF unit through a single InternetProtocol/Peer-to-Peer Protocol (IP/PPP) layer included in its own CSDprotocol layer, and the IWF unit communicates through the Internet witheach of the WAP servers.
 2. The device of claim 1, wherein the IWF unitincludes a mapping table used for mapping each of the WAP terminals tothe corresponding WAP server, wherein identification numbers of each ofthe WAP terminals and destination IP addresses of each of the WAPservers are mapped to each other, or source IP addresses of each of theWAP terminals are mapped to the corresponding mapping table values.
 3. Acommunication method of a data communications device including aplurality of WAP terminals each having a protocol stack in which aCircuit Switch Data service (CSD) protocol layer is laid under aWireless Transaction Protocol (WTP) layer and a Wireless DatagramProtocol (WDP) layer, a non-WAP terminal for generating a common circuitdata, a plurality of WAP servers each having a protocol stack in whichat least a Transmission Control Protocol (TCP) layer and an InternetProtocol (IP) layer are laid under a WTP layer and a WDP layer, anInternet server for providing the non-WAP terminal with Internet serverdata according to the common circuit data, an Internet service provider(ISP) having a public switched telephone network (PSTN) circuit layer,for transferring the common circuit data received through a PSTN fromthe non-WAP terminal to the Internet server, an interworking function(IWF) unit having a CSD protocol layer connected to the CSD protocollayers of each WAP terminal, and a TCP layer and an IP layer which areconnected to the TCP and IP layers of each WAP server, for datacommunications between each WAP terminal and each WAP server, the methodcomprising the steps of: (a) determining whether data input to the IWFunit is WAP data or the common circuit data; (b) transferring the WAPdata through the Internet to the corresponding WAP server if the inputdata is determined to be the WAP data in the step (a) and transferringthe common circuit data through the ISP to the Internet server if theinput data is determined to be the common circuit data in the step (b);(c) determining whether the data input to the IWF unit is WAP serverdata or the Internet server data; and (d) transferring the WAP serverdata through the Internet to the corresponding WAP terminal if the inputdata is determined to be the WAP server data in the step (c), andtransferring the Internet server data through the PSTN to the non-WAPterminal if the input data is determined to be the Internet server datain the step (c), wherein each WAP terminal communicates with the IWFunit through a single Internet Protocol/Peer-to-Peer Protocol (IP/PPP)layer included in its own CSD protocol layer.
 4. A computer usablemedium having a computer readable program code unit embodied therein forcommunications transferred between a WAP terminal and a WAP server of adata communications device including a plurality of WAP terminals eachhaving a protocol stack in which a CSD protocol layer is laid under aWireless Transaction Protocol (WTP) layer and a WDP layer, a non-WAPterminal for generating a common circuit data, a plurality of WAPservers each having a protocol stack in which at least a TCP layer andan IP layer are laid under a WTP layer and a WDP layer, an Internetserver for providing the non-WAP terminal with Internet server dataaccording to the common circuit data, an ISP having a PSTN circuitlayer, for transferring the common circuit data received through a PSTNfrom the non-WAP terminal, to the Internet server, an IWF unit having aCSD protocol layer connected to the CSD protocol layers of each of theWAP terminals, and a TCP layer and an IP layer which are connected tothe TCP and IP layers of each of the WAP servers, wherein each of theWAP terminals communicates through a single IP/PPP protocol layerincluded in its own CSD protocol layer to the IWF unit, the computerreadable program code means in the computer usable medium comprising:first computer readable program code means for causing a computer toeffect determining whether data input to the IWF unit is WAP data or thecommon circuit data; second computer readable program code means forcausing the computer to effect transferring the WAP data through theInternet to a corresponding one of the WAP servers if the input data isdetermined as the WAP data and transferring the common circuit datathrough the ISP to the Internet server if the input data is determinedto be the common circuit data; third computer readable program codemeans for causing the computer to effect determining whether the datainput to the IWF unit is WAP server data or the Internet server data;and fourth computer readable program code means for causing the computerto effect transferring the WAP server data through the Internet to acorresponding one of the WAP terminals if the input data is determinedto be the WAP server data, and transferring the Internet server datathrough the PSTN to the non-WAP terminal if the input data is determinedto be the Internet server data.